"Shock tactics don't work in personal statements," Dr Kevin Murphy, admissions tutor for medicine at Imperial College London, says. "Sometimes candidates describe a scene from their work experience where someone gets their leg sawn off in the jungle – or something similar. But that's not the most effective way to start."

Some medical schools take personal statements more seriously than others – while Cardiff, Leeds and Keele formally assess non-academic aspects of a student's application, other universities, including Oxford and Imperial, use them more informally to get an impression of a candidate's suitability.

They all agree, though, that a personal statement gives students a chance to relay what they've learned from work experience and demonstrate that they have the non-academic skills required for medicine.

"Becoming a doctor is hard work," says Helen Diffenthal, assistant principal of Farnborough sixth-form college in Hampshire. "So use a personal statement to demonstrate your commitment, and that you won't give up when the going gets tough."

One way to show tutors that you are committed is through your work experience. Use it to prove that you have a realistic view of the profession.

Admissions tutors warn against naming places where you have worked, without any reflection on your time there. "Too often we get applications that look like a shopping list," says Paul Teulon, director of admissions at Kings College London. "We'd like to hear about a patient a student has come into contact with, or an experience they've had. It's just as valuable to have spent time with a hospital porter, as it is to have followed around the lead clinician."

Think also about the things you've done outside of school and how they demonstrate your skills. Teulon says: "A student might be involved with scouting or guiding, in a church group, or have done the Duke of Edinburgh."

Don't be afraid to include more unusual activities, as these can stand out. "If you were in a rock band, you could explain that you formed, led and developed it," Mike Jennings, senior lecturer at Sheffield Medical School, says. "Students might think a medical school won't be interested in that, but it shows staying power, teamwork and leadership."

Medical schools give varying advice on how to structure a personal statement, and about what skills they want applicants to demonstrate. This can make it difficult for students who want to impress a range of schools with one application.

"It can be a minefield for an applicant to work out whether they meet the criteria for different medical schools," admits Dr Austen Spruce, who is in charge of admissions for medicine at Birmingham University. "I advise students to write their personal statement to the highest threshold set by any of the universities, and then it will meet the criteria for all of them."

If you're applying to more than one school, check to see if they ask for different skills. "There's a certain amount of game-playing involved," Mike Jennings explains. "Applicants can phrase something in a certain way to meet more than one school's requirements."

When you've figured out what to include, it can be difficult to know how to begin your personal statement. Some teachers advise pupils to start with the second paragraph, get the statement written, and then pull out an interesting sentence or quote to use as an introduction.

"We tell them to write the first paragraph last," explains Diffenthal. "The first paragraph is often the weakest, so start with the second – a sentence about your experience might stand out and you can reorganise it afterwards."

What introductions should students avoid? "The weakest personal statements begin with 'I want to do medicine because my grandfather had a disease'," says Kim Piper, from the school of medicine at Queen Mary University. "I'd be nervous about someone who wanted to go into medicine for personal reasons, because they could be a nurse rather than a doctor."

While a well-written and coherent application is a must, students should be careful not to use overly complicated language. "Don't write your personal statement and then use a thesaurus to make it sound more grandiose," Paul Teulon says. "You're not using the language you would normally use, and that comes across."

The difficulty is in trying to tell everyone how fantastic you are, without being boastful, says Murphy. "It's a hard line to toe. I warn people against making grand pronouncements that they know they'll make a great doctor."

Ask for help if you need it, but avoid asking too many teachers or family members to go over your personal statement. "We want to hear the voice of a young person," says Teulon, "not a 55-year-old parent. I don't mind if they say they want to change the world because, frankly, if you can't say that at 18, I don't know when you can."

So be honest. Explain how you came to love medicine, and why you will be able to cope with a course that is tough, demanding and competitive. "The goal should be to receive one offer," says Paul Teulon. "Any more than that is a bonus."

And once you've sent it in, keep a copy of your personal statement and be prepared to back up everything you've written, because some medical schools will use it as a prop for an interview.